Bring 4 cups of water to a boil in a large saucepan.
Add tea leaves and baking soda. Simmer on low heat for 10–15 minutes until reduced by half.
Add cold water (about 1 cup) and simmer again for 5 minutes.
Strain the liquid and return to the pan.
Stir in milk, sugar, salt, and cardamom. Simmer for another 10 minutes.
Pour into cups and top with chopped pistachios and almonds before serving.